/in/foo.cc: In function 'void dfs(int)':
/in/foo.cc:10:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<numh[now].size();++i){
              ~^~~~~~~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:29:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=1;i<=n;++i){
              ~^~~
/in/foo.cc:36:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=1;i<=n;++i)
              ~^~~